mctighe



(No Model.)

J. & T. J. McTIGHE.

ELECTRIC LAMP.

No. 246,178. Patented Aug. 23,1881.

WITNESSES:

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UNITED STATES PATENT OFFICE.

JAMES MOTIGHE AND THOMAS J. MGTIGHE, OF PITTSBURG, PA.

ELECTRIC LAMP.

SPECIFICATION formingpart of Letters Patent No. 246,178, dated August 23, 1881.

Application filed April 18,1881. (NomodcL) To all whom it may concern Be it known that we, JAMEs J. MOTIGHE and THOMAS J. MGTIGHE,of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Electric Lamps, and we do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being bad. to the accompanying drawings, which form a part of this specification.

Our invention has reference to the construe tion of electric lamps of the arc type, and comprises mechanism and arrangements for feeding the positive carbon downwardly to a stationarynegative carbon, for feeding the positive and negative carbons toward each other to obtain a focusing-lamp, and to connect the two binding-posts directly the moment the carbons for any cause fail to pass the current, and thus dispense with that lamp in a series The invention consists in the devices hereinafter described whereby, previous to the passage of the current into the lamp, two paths exist for the current of substantially equal resistance, one being the carbons and magnet, and the instant the current passes through said carbons and magnet the other circuit is completely out, thus throwing all the current into the carbons; and in the construction and combination of parts, substantially as hereinafter fully described and claimed.

In the drawings, Figure 1 is a sectional elevation of our improved lamp complete. Fig. 2 is a detail.

' Adesignates asupporting-disk,of hard rub,- ber or other similar non-conductor, having-the binding-posts B C. An opening is made at the center of disk A large enough to permit the free movement of the carbon, which may be guided in a true vertical line by a tube placed above the disk, if desired. A tubular piece of soft iron, D, is fixed to the disk Aon its under face, and in this we place the coil E,

one of whose terminals is connected with post B, and the other of which is connected electrically with the body of metal D or tubular magnet. A disk-armature, F, of soft iron, having a central opening larger than the carbon to be employed, is held within attractive distance of the lower end or poles of the tubular magnet D by means of the platform or frame-work G,

which is adjustably fixed to the magnet D by means of the screws a, which pass through and form guides for the disk-armature F. Two contact spring-plates, b, are fixed to frame G, whose tension is so fixed that while pressing upon the carbon and making a good contact therewith they do not prevent its descent whenitisotherwisefreetodescend. Attached to armature F and converging upwardly are two opposite spring-clutches, c, which enter an enlarged recess in the core of the magnet D. Magnet D-is bored'out to allow the positive carbon H to pass freely. Spring-clutches c are so arranged that when the armature F is not attracted toward the magnet they do not touch the carbon; but when attraction is exerted and the armature F is lifted sufficiently they are compressed by the sides of the recess in the core and grasp the carbon tightly, and the further attraction of armature F elevates the carbon H. The current passes from post B to coil E, thence to magnet-body D, thence by screws a to frame G and disk-armature F, whence it passes to the carbon H by the springs I), thus delivering the current into the carbon within an inch or two of the arc.

For the present we will consider the lower carbon, I, (negative,) as fixed, being supported by the ordinary means in the frames J J, which conduct the current from the negative carbon back to the disk A. Frame J is connected by plate at and screw 0 to binding-post C. Now, the current would ordinarily pass from post B, through coil E, magnet-body D,

screws (1, frame G, springs 11 0, carbon H, are,

carbon I, and thence to post 0 by way of frame J, screw 6, and plate 61, frames J J being integral. Post B, by plate f, is also in contact with an adjustable contact, K. A spring-contact, g, is attached to frame J, as shown. An elbow-lever, L, is pivoted to the side of magnet D and carries the hard-rubber blockt' at its upper end, and at its lower end the small softiron sub-armature M, whose duties are twofold. A retractin g-sprin g, k, is adj ustably attached'to the lever, normally pressing it away from magnet D. llow, before the current is admitted to the terminals B O the conditions are, both carbons are in contact and spring-contact'g is touching contact K. Therefore, when the current is admitted to post B, it divides, and the circuits being of practically no resistance, the half goes through coil E,iron D, screws a, frame G, carbons H I, and frame J, to post G, and the other half goes from post B, through plate f, contact K, into spring 9, to frame J, thence to frame J, and out atC; but the moment attraction is set up in magnet D the subarmature M is drawn toward it, and the contact at y K broken, whereupon the whole current is afforded only the single pathway through coil E and its accessories and carbons H 1. Coil E, receiving all the current, now at tracts the armature F. The first movement of armature F compresses the springs 0 upon carbon H, and the further movement lifts the carbon H and establishes the are. As the carbon H burns away and the resistance of the are increases, the attractive power of magnet D decreases, and the armature Ffalls more or less. In falling it pulls carbon H downward positively, and this action is repeated until armature F lowers to a point where clutches c are no longer compressed by the magnet D, and then the carbon is free to fall farther by its own gravity-to assist which is the additional initial impulse imparted to it from the armature F-thus feeding downward a fresh portion of the carbon. Meanwhile the attraction, though too weak to maintain the armature F in a constant position, is still sufficient to retain the sub-armatu re M in attracted position, thus keeping open the switch at g K. Now, should the current at any time become abnormally great in the lamp and produce an arc abnormally great, the armature F will be attracted to the fullest extent right up against the magnet D, pushing in the pins n, which are normally projecting downwardly by the force of springs m, (the tension of the latter being adjustable by the screw-plugs o in edges of magnet D,) thus closing the magnetic field between the two poles of the tubular magnet D through armature F, and the attraction for the sub-armature M becomes practically inoperative, whereupon spring It acts and closes switch 9 K automatically. This causes the current to divideinto the two circuits, as before described, the attraction for armature F is weakened, and the latter drops and shortens the are, and prevents that lamp from using too much current or producing too great an arc, to the detriment of other lamps in the circuit. The spring-pins a are adjusted so as to prevent the contact of armature F with magnet D, except when an abnormally great current passes through the lamp.

Should the carbons fail to feed or one of them break, or should the current for any reason fail to pass through the carbons properly, the armature F drops by reason of the lessened or nullified attraction of magnet D. At the same instant the sub-armature M is free, and its spring causes the switch 9 K to close, whereupon all the current is passed around the lamp, and it is cut out of the series.

To make a focusing-lamp, it is necessary to provide an automatic feed for the negative carbon, which we do in the following way: At the lower part of frame J J we attach a tubular magnet, D, exactly similar to magnet D above, and placed with its poles facing downwardly like I), and arranged just the same as magnet D. A coil, E, is placed inside of it, one terminal being in contact with frame J and the other in contact with the body D of the magnet. On top of magnet D are two contact-springs, 1), whose office is to convey the current to carbon I, and they press upon the carbon sufficiently to prevent its fall by gravitation. A disk-armature, F ,is arranged below magnet D by means of the screws aand platform G, just the same as the armature F above, and is provided with the springclutches c, constructed and arranged similarly to clutches c on the upper carbon.

An insulating-ring, s, separates frame J J from magnet I). Carbon I being in position, the current comes down from carbon H to carbon Iinto contacts I) and clutches c, thence into body D, thence through cell E to frame J J, whence it passes to binding-post G by screw 0 and plate (I. The position of platform G is such that the play of armature F can be only about half that of armature F.

Thus arranged, the operations are as follows: Before any current is admitted to the lamp the carbons H I are supposed to be setin contact with each other. When the current passes both coils E and E are rendered active, and the magnets D D attract their respective armatures F F. Now, according to the specified adjustments, armature F lifts carbon H, say, four millimeters. At the same instant carbon I is lifted only two millimeters, so that the are established will be two millimeters in length. Now, as the carbons burn away, the tendency is for the current to weaken, thus permitting the upper carbon to lower gradually by the positive action of the clutches a. At the same time clutches a draw carbon I downward,but only to half the extent of the movement ofcarbon H. As before stated, a time comes when the clutches 0 let go and carbon H drops by its own gravity. At this instant, or before it, if desired, clutches 0 let go of carbon I and fall with armature F, while carbon I is held stationary by springs b, and thus the clutches 0 get a fresh hold on carbon I. These movements are repeated constantly, but they take place to an almost imperceptible extent each time, and the result is that the upper carbon, burning away twice as fast as the negative carbon, is fed downwardly twice as fast as the lower carbon is fed upwardly; but the movements of both do not take place except when the arc and the current require them in order to maintain constant conditions, and then the movements take place by the action of electro magnetic devices setin operation automatically by the current itself, as described.

By using the described tubular magnets we obtain against the armature the superior attractive power of the two poles, and consequent- 15' the magnetic field is rendered extremely sensitive to the changes taking place in the current. Besides, the tubular form receives magnetic inductionfrom the inside and outside layers of the coil, and we are thus enabled to obtain the necessary effects with but a few turns of coarse wire, thereby dispensing with a detrimental resistance in such coils and reducing the resistance of the lamp exterior to the are and carbons practically to ml, and the tubular magnets, having an open center, as have also the disk-armature, allow the carbons to pass through on the axis, and we are thus enabled to use carbons of any length, since the feeding mechanism is not in the axis, but is concentric therewith.

We claim as our invention 1. In an electric lamp, in combination with the carbon-feeding helix and carbons, an independent conductor aroundsaid helix and carbons, provided with an electromagnetic cutoff, substantially as described, whereby the said independent conductor is automatically opened or out upon the passage of a current and closed by a cessation of current.

2. I11 an electric lamp, an electrical helix of substantially no resistance in circuit with the electrodes, in combination with two conductors of substantially no resistance, connected respectively to the main line on opposite sides of the helix and electrode circuit, a spring circult-closer constructed and adapted to normally and adapted to feed the negative carbon upwardly" at substantially halt the speed of descent of the positive carbon.

4. The combination of hollow tubular magnet D E, disk-armature F, convergent springclutches 0, frame G, and carbon H, said magnet D E having a shouldered recess for the reception of the clutches c, substantially as described.

5. The combination of magnet D E in the carbon circuit with sub-armature M, lever L, spring 70, contacts 9 K, and plate orconductor f, connected to post B, said contact 9 being in direct circuit with post 0, substantially as described.

In testimony that we claim the foregoing as our own we have hereto affixed our signatures in presence of two witnesses JAMES J. MG'IIGHE. THOMAS J. MGTIGHE.

Witnesses p F. J. PATTERSON, A. V. D. WAT'IERSON. 

